Sliding contact surface-forming material, and multi-layered sliding contact component having the same

Abstract

A sliding contact surface-forming material includes a reinforcing base impregnated with a resol-type phenolic resin having polytetrafluoroethylene resin dispersed therein. The reinforcing base being composed of a woven fabric formed by using, respectively as the warp and the weft, a ply yarn which is formed by paralleling at least two strands of a single twist yarn spun from fluorine-containing resin fiber and a single twist yarn spun from polyester fiber, and by twisting them in the direction opposite to the direction in which the single twist yarns were spun Additionally, a multi-layered sliding contact component having the overall shape of a flat plate or a circular cylinder includes the above-described sliding contact surface-forming material so as to configure at least the sliding-contact surface thereof.

Description

TECHNICAL FIELD[0001]The present invention relates to a sliding contact surface-forming material used for sliding contact components such as slide bearing, and a multi-layered sliding contact component having the sliding contact surface-forming material for the sliding contact surface thereof.BACKGROUND ART[0002]There have been well-known sliding contact component having flat or circular cylindrical geometry, configured by stacking resin work materials each composed of cotton fabric, as a reinforcing base, impregnated with a thermosetting synthetic resin such as phenolic resin and epoxy resin, or with a resin composition composed of the thermosetting resin added with polytetrafluoroethylene resin (Patent Document 1). The sliding contact component are adopted in a wide variety of fields, including wear ring fitted to the outer circumferential surface of piston of hydraulic cylinder, underwater slide bearing and so forth, by virtue of its excellence in the wear resistance, load resist...

AI Technical Summary

Benefits of technology

[0037]Since the reinforcing base, which is composed of a woven fabric formed by using, respectively as the warp and the weft, a ply yarn formed by paralleling at least two strands of a single twist yarn spun from fluorine-containing resin fiber and a single twist yarn spun from polyester fiber, and by twisting them in the direction opposite to the direction in which the single twist yarns were spun, allows the fluorine-containing resin fiber and the polyester fiber to expose on at least one surface thereof which serves as the sliding contact surface, while keeping almost equal areas of exposure, so that the present invention successfully provides a sliding contact surface-forming material, improved in the friction-proof and wear-proof characteristics, contributed also by low friction properties of the PTFE powder impregnated into the reinforcing base.

[0038]Since the woven fabric as the reinforcing base, woven using the ply yarn as the warp and weft, may be made thicker than a flat-woven fabric typically woven by using single twist yarn, so that the multi-layered sliding contact component, integrally having the sliding contact surface-forming material impregnated with a specific resol-type phenolic resin containing PTFE powder, may be subjected to machining, and thereby improving dimensional accuracy of the multi-layered sliding contact component.

[0039]The resol-type phenolic resin preferably used in the present invention is synthesized by allowing a phenolic compound which contains 50 to 100 mol % of bisphenol A to react with a formaldehyde compound, while being catalyzed by an amine compound, has a number-average molecular weight Mn, measured by gel permeation chromatography (GPC), of 500 to 1000, and has a distribution index Mw / Mn, given as a ratio of weight-average molecular weight Mw and number-average molecular weight Mn, of 2.5 to 15. The phenolic resin exhibits a good affinity with the hydrophobic polyester fiber, so that it may thoroughly be impregnated into the flat-woven fabric, and may therefore tightly adhere thereto. Accordingly, the surface treatment of the woven fabric containing polyester fiber, which has been necessary in the prior art, is no longer necessary.

Problems solved by technology

The circular cylindrical multi-layered sliding contact component manufactured using the fiber-reinforced resin composition composed of the cotton fabric and the phenolic resin has, however, been facing difficulty in keeping a constant clearance (gap of sliding contact) with respect to the opposing shaft, when used in a humid atmosphere or underwater, due to swelling and dimensional changes as a consequence.

The synthetic resins having these advantages, however, suffer from their poor adhesiveness to resins, when intended to achieve a satisfactory level of reinforcing effect with respect to the resins.

It is, however, difficult to adhere the intact polyester fiber to the unsaturated polyester resin, due to a poor content of functional groups in the polyester fiber.

(1) poor workability and very strong toxicity in some cases;

(2) treatment liquid is readily affected by temperature and humidity, and less stable;

(3) high cost due to need of large volume of treatment liquid; and

(4) the synthetic fibers per se are degraded in some cases.

It is therefore understood that no techniques, capable of obtaining sufficient levels of improvement in the adhesiveness and safety, have been established as the methods of surface treatment of synthetic fibers.

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